Espresso is a concentrated coffee beverage brewed by forcing heated pressurized water through ground coffee beans. By forcing heated pressurized water through ground coffee beans, the beverage produced during an espresso brewing process absorbs more of the flavor producing components, such as the oils and various solids found in the beans. As compared to coffee beverages produced by other brewing methods, such as drip brewing, an espresso brewing process results in a thicker beverage with a creamy texture and a concentrated and complex taste profile. Also, because the water is under pressure, the coffee grounds used for espresso may be ground finer than the coffee grounds used for other brewing processes. This results in greater surface area of coffee grounds for which the pressurized water can come into contact with, absorbing more of the flavor producing chemicals from within the grounds. Furthermore, for an espresso brewing process, the grounds may be tamped to provide a greater stacking efficiency of the grounds, which promotes the water's penetration of the grounds, resulting in still greater flavor extraction.
Because of its relatively high concentration, as compared to other coffee beverages, espresso may be served in a small portion referred to as a shot, measuring approximately 1 U.S. fluid ounce. Espresso may also be served in integer multiples of a shot, such as a double shot or a triple shot. Espresso is typically prepared using a specialized coffee machine, referred to as an espresso machine. Brewing a shot of espresso may be referred to as pulling a shot of espresso because some espresso machines require a user of the machine, or a barista, to pull a spring loaded lever that is attached to a piston, where pressure created by the piston forces the water through the coffee grounds. Although the construction of espresso machines may vary, the machines are often loosely categorized by the drive mechanism used to produce the required pressure. One popular method used to produce the pressure is to employ a motor driven pump. Machines that employ such a pump are often collectively referred to as pump-driven, or simply pump espresso machines.
Espresso is a popular beverage worldwide. In addition to serving espresso as a shot, espresso may be used as a base for other popular coffee beverages, such as cappuccinos, lattes, macchiatos, and americanos. Some preparations of espresso based beverages may use wet steam to heat and/or froth milk. Many espresso machines are able to supply the heat and pressure required to brew espresso. In addition, some machines may supply heat and pressure to generate the wet steam that is used in the preparation of various espresso based beverages. Thus, it is with respect to these and other considerations that the present invention has been made.